21716772 has 96 divisors (see below), whose sum is σ = 66554880. Its totient is φ = 5339520.

The previous prime is 21716767. The next prime is 21716809. The reversal of 21716772 is 27761712.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16938 + ... + 18174.

It is an arithmetic number, because the mean of its divisors is an integer number (693280).

Almost surely, 2^21716772 is an apocalyptic number.

21716772 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21716772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33277440).

21716772 is an abundant number, since it is smaller than the sum of its proper divisors (44838108).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21716772 is a wasteful number, since it uses less digits than its factorization.

21716772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1281 (or 1279 counting only the distinct ones).

The product of its digits is 8232, while the sum is 33.

The square root of 21716772 is about 4660.1257493763. The cubic root of 21716772 is about 278.9962872542.

The spelling of 21716772 in words is "twenty-one million, seven hundred sixteen thousand, seven hundred seventy-two".